1. Field of the Invention
The present invention has specific application in the areas of CW and pulse communications, radar receiver systems, signal acquisition and measurement, RF signal processing, and signal digitization, and in general wherever there is a need for automatic gain control (AGC) with high stability, high speed and low distortion. It is particularly suited for pulse systems where there is a need for signal amplitude control on a pulse-to-pulse basis and with a minimum of signal distortion.
2. Description of Related Art
The related prior art includes diverse circuitry for controlling the gain or attenuation applied to an input signal during the processing thereof. Examples of such prior art include:
Angelle et al U.S. Pat. No. 3,936,819 which teaches circuitry for sampling an input analog signal, applying gain in discrete steps until the signal is within a certain range, and then digitizing the amplified signal;
Schanne et al U.S. Pat. No. 4,540,974 which teaches circuitry useful for adjusting the amplitude of a television signal, including means for taking an input analog signal, digitizing it, and dependent on statistics generated via the digitization process, applying an attenuation or amplification to the signal as needed to place the output signal in an acceptable range; and
Baars et al U.S. Pat. No. 4,831,378 which teaches an analog-to-digital converter having an automatic gain control circuit to avoid saturation at the output of the A/D converter.